The 640 is way cheaper, has a slightly bigger battery and a better rear camera (8MP vs 6.7MP).
The 735 has an oled display (no glance) and a better front facing camera (5MP vs 1MP).
IMO the 735 has a better design, but the 640 seems the clear winner here.
I'm hoping the 740 will come soon or I'll go for the 640.
Did you know that the 640 does not have NFC capability compared to the 735?
A 740? I've not heard anything about a 740. Is that purely vaporware?
No, I did not know that the 640 didn't support NFC. Is that because its a mid-range phone? In any case thank you for letting me know.